Sometime before or later, Gral was on Risa playing a game with several people, including a Human. Gral had a receiver in his lobes through which Krax and others guided him through the game. Gral was exposed when the Human next to him heard the receiver, which had been improperly placed by Krax. (DS9novel: The Big Game)

The above event could be the reason why Gral and Krax were antagonistic towards each other in "The Nagus" if it took place before the meeting on DS9. The script of episode indicated that there was "no love lost" between them.